Preliminary studies suggest that inhibition may be a risk factor for the development of childhood psychopathology, particularly the anxiety disorders. The proposed research will examine the relationship between inhibition and childhood psychopathology. Two independent cohorts of children will be assessed at age 12-13. each cohort was originally selected at either 21 or 31 months of age because they showed pronounced inhibited or uninhibited behavior with unfamiliar people, procedures, and objects in unfamiliar laboratory settings. Three types of assessments will be used: 1) a semi-structured psychiatric interview generating diagnosis based on the DSM-III-R criteria; 2) a laboratory based psychophysiology assessment; and 3) a direct observation of behavior in a group situation in the laboratory. The aims in this research are: 1) to examine the relationship between inhibited and uninhibited child temperament, and the subsequent development of child and adolescent psychopathology; 2) to examine behavioral and physiological stability and change of temperamental type into early adolescence; 3) to examine the predictive value of prior psychophysiological assessments made as early as 21/31 months and the subsequent development of psychopathology; 4) to examine the relationship of contemporary psychophysiology to: a) past or current psychopathology, b) previous temperamental type, and c) current behavior as assessed by direct observation in the laboratory. This supervised research experience will combine Dr. Schwartz's previous experience in psychopathology and high risk research, with a career development plan to educate Dr. Schwartz in the approaches of developmental psychology. The candidate will learn in a hands-on way the approach to the laboratory based study of complex behavior. Techniques to be learned include psychophysiological and direct observational assessment, as detailed in the research plan. The career development plan also includes a didactic component with courses and seminars in developmental psychology and biostatistics. The acquisition of these new skills and this conceptual knowledge, when integrated with Dr. Schwartz's previous experience in psychiatric research will enable him to conduct longitudinal developmental psychopathological research that combines a developmental perspective with the simultaneous assessment of biological parameters.